Mail tester daemon.
Fake a SMTP server and print email to stdout.
It binds to port 25 by default, so probably you will have to sudo it. If you want to run it in a different port, pass the port number as the first argument.
$ mt
# Email contents will be displayed here.
$ mt 2525
# Tell mt to bind to port 2525 instead.
$ mt &
# Run it in the background.You can install it using rubygems.
$ gem install mt